From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 80007C433ED for ; Fri, 23 Apr 2021 10:17:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 296BE61139 for ; Fri, 23 Apr 2021 10:17:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241897AbhDWKSA (ORCPT ); Fri, 23 Apr 2021 06:18:00 -0400 Received: from smtp04.smtpout.orange.fr ([80.12.242.126]:47743 "EHLO smtp.smtpout.orange.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229823AbhDWKRr (ORCPT ); Fri, 23 Apr 2021 06:17:47 -0400 Received: from [192.168.1.18] ([86.243.172.93]) by mwinf5d51 with ME id wAH82400W21Fzsu03AH8EJ; Fri, 23 Apr 2021 12:17:09 +0200 X-ME-Helo: [192.168.1.18] X-ME-Auth: Y2hyaXN0b3BoZS5qYWlsbGV0QHdhbmFkb28uZnI= X-ME-Date: Fri, 23 Apr 2021 12:17:09 +0200 X-ME-IP: 86.243.172.93 Subject: Re: [PATCH] nvmem: core: add a missing of_node_put To: Srinivas Kandagatla , bgolaszewski@baylibre.com, gregkh@linuxfoundation.org Cc: linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org References: <2ebc18d9da622afe8681c18349b501a516253041.1618949512.git.christophe.jaillet@wanadoo.fr> <93e8b92c-8f4e-9990-ac4d-9688bbaaa6f6@linaro.org> From: Christophe JAILLET Message-ID: Date: Fri, 23 Apr 2021 12:17:07 +0200 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.10.0 MIME-Version: 1.0 In-Reply-To: <93e8b92c-8f4e-9990-ac4d-9688bbaaa6f6@linaro.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Le 23/04/2021 à 11:30, Srinivas Kandagatla a écrit : > > > On 20/04/2021 21:12, Christophe JAILLET wrote: >> 'for_each_child_of_node' performs an of_node_get on each iteration, so a >> return from the middle of the loop requires an of_node_put. >> >> Fixes: e888d445ac33 ("nvmem: resolve cells from DT at registration time") >> Signed-off-by: Christophe JAILLET >> --- >>   drivers/nvmem/core.c | 6 +++++- >>   1 file changed, 5 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c >> index bca671ff4e54..4375e52ba6c2 100644 >> --- a/drivers/nvmem/core.c >> +++ b/drivers/nvmem/core.c >> @@ -686,12 +686,15 @@ static int nvmem_add_cells_from_of(struct >> nvmem_device *nvmem) >>               continue; >>           if (len < 2 * sizeof(u32)) { >>               dev_err(dev, "nvmem: invalid reg on %pOF\n", child); >> +            of_node_put(child); >>               return -EINVAL; >>           } >>           cell = kzalloc(sizeof(*cell), GFP_KERNEL); >> -        if (!cell) >> +        if (!cell) { >> +            of_node_put(child); >>               return -ENOMEM; >> +        } >>           cell->nvmem = nvmem; >>           cell->np = of_node_get(child); >> @@ -717,6 +720,7 @@ static int nvmem_add_cells_from_of(struct >> nvmem_device *nvmem) >>               kfree_const(cell->name); >>               of_node_put(cell->np); >>               kfree(cell); >> +            of_node_put(child); > > two of_node_put looks bit confusing to the reader, can you move the > > cell->np = of_node_get(child); just before nvmem_cell_add(cell); > so that we can remove extra put. > Sure. I didn't pay attention that cell->np and child were the same and that the code looked odd now. Thx for the review and the comment. > Was this reported by some kind of static analysis tool? > Yes, this was found by coccinelle. The script used was an old one posted by Julia Lawall a few years ago: // @r@ local idexpression n; expression e1,e2; iterator name for_each_node_by_name, for_each_node_by_type, for_each_compatible_node, for_each_matching_node, for_each_matching_node_and_match, for_each_child_of_node, for_each_available_child_of_node, for_each_node_with_property; iterator i; statement S; expression list [n1] es; @@ ( ( for_each_node_by_name(n,e1) S | for_each_node_by_type(n,e1) S | for_each_compatible_node(n,e1,e2) S | for_each_matching_node(n,e1) S | for_each_matching_node_and_match(n,e1,e2) S | for_each_child_of_node(e1,n) S | for_each_available_child_of_node(e1,n) S | for_each_node_with_property(n,e1) S ) & i(es,n,...) S ) @@ local idexpression r.n; iterator r.i; expression e; expression list [r.n1] es; @@ i(es,n,...) { ... ( of_node_put(n); | e = n | return n; | + of_node_put(n); ? return ...; ) ... } @@ local idexpression r.n; iterator r.i; expression e; expression list [r.n1] es; @@ i(es,n,...) { ... ( of_node_put(n); | e = n | + of_node_put(n); ? break; ) ... } ... when != n @@ local idexpression r.n; iterator r.i; expression e; identifier l; expression list [r.n1] es; @@ i(es,n,...) { ... ( of_node_put(n); | e = n | + of_node_put(n); ? goto l; ) ... } ... l: ... when != n // > > --srini > > > >>               return -EINVAL; >>           } >> >